Apparatus for handling material

ABSTRACT

An apparatus is described for use in converting an electromagnetic grab to function as a mechanical grab. The apparatus includes a frame within which the magnet block of a conventional electro-magetic grab is locatible and a two part core assembly of magnetic material hydraulically coupled to the grab arms of the apparatus. Energisation of the magnet block causes progressive movement of the core assembly towards the block actuating closing movement of the arms, whilst a hydraulic reservoir assists in procuring movement of the arms after de-energisation of the magnet block.

United States Patent [191 Laws et a1.

[ APPARATUS FOR HANDLING MATERIAL [75] Inventors: William Robert Laws,Worcester 7 Park; Erie Ambrose Hyde, Hayes,

both of England [73] Assignee: The British Iron and Steel ResearchAssociation, London, England [22] Filed: Feb. 6, 1973 [21] App]. No.:329,984

[30] Foreign Application Priority Data Feb. 23,1972 Great Britain8379/72 [52] US. Cl 294/88, 294/655, 294/106, 214/114, 214/147 G [51]Int. Cl. B666 1/06, B666 3/16 [58] Field of Search 294/655, 88, 106;37/183 R,183 A, 187; 214/147 G, 114;

[56] 1 References Cited UNITED STATES PATENTS Naugle et a1 H 214/114Mar. 26, 1974 2,651,538 9/1953 Stahmer 294/655 2,850,189 9/1958 Leroy214/114 FOREIGN PATENTS OR APPLICATIONS 958,539 5/1964 Great Britain,294/655 188,832 11/1922 Great Britain 294/655 Primary Examiner--Evon C.Blunik Assistant Examiner-John ny D. Cherry Attorney, Agent, orFirm-Bacon & Thomas 5 7 ABSTRACT An apparatus is described for use inconverting an electro-magnetic grab to function as a mechanical grab.The apparatus includes a frame within which the magnet block of aconventional electro-magetic grab is locatible and a two part coreassembly of magnetic material hydraulically coupled to the grab arms ofthe apparatus. Energisation of the magnet block causes progressivemovement of the core assembly towards the block actuating closingmovement of the arms, whilst a hydraulic reservoir assists in procuringmovement of the arms after de-energisation of the magnet block.

6 Claims, 4 Drawing Figures PATENIEUMARZS mm 37991502 SHEETIUFZ FIG).

AV///K\V /A\7// AV AV///AV AV/ FIG. 3.

APPARATUS FOR HANDLING MATERIAL Apparatus has already been proposed forhandling material such as scrap metal by modifying a conventional magnetblock suspended from a crane. Accordy from the problem that theattractive force between the core and the block varies as the inversesquare of the distance between them so that the closing force on thearms is smallest when the arms are in the fully open position.Consequently when handling a large and heavy load the attractive forceof the magnet block may sometimes be insufficient to start the closingmovement of the arms. An object of this invention is to reduce thisproblem.

According. to the present invention there is provided apparatusattachable to an electro-magnetic grab for handling non-magneticmaterials including: a frame connectible to. the grab, lifting armsmovable relative to the frame, and a core movable relative to the frame,the arms and the core being operatively connected together so that, inuse, when the frame is connected to the grab, energisation of the magnetblock of the grab will attract the core towards the block thus closingthe armsinto a material-holding position, subsequent deenergisation ofthe block allowing the arms to open into a fully open material-releasingposition, the core being formed in two parts of magnetic materialcapable of limited relative movement, the parts being arranged sothat'in the'fully open position of the arms the first part is locatedcloser to the magnet block than the second part, movement of said firstpart towards the block carrying said second part towards the block andpartially closing the arms, the said second part being capable offurther movement towards the block after the first part has moved itsfull extent in order to complete the closing movement ofthe arms.

By forming the core in at least two parts in accordance with theinvention the distancesbetween one core part and the block can be keptsufficiently small to ensure an adequate attractive force to begin theclosing movement of the arms. Movement of the other part relative to thefirst part towards the block enables full closing'movement of the armsto take place.

Although the operative connection betweenthe core assembly and the armsmay be a simple mechanical connection, preferably the second part of thecore assembly is connected to a piston and cylinder assembly arranged sothat upon movement of said second part towards the magnet block fluid isdisplaced to actuate fluid operated rams connected to the arms. Such ahydraulic connection enables the small amount of movement of the coreassembly to be conveniently translated into a large movement of thearms.

Upon de-energisation of the magnet block there is residual magnetismleft in the block which will hold the core parts close to the magnetblock unless the separatingforces can overcome this. Accordingly it maybe desirable to have a pressurisable fluid reservoir operativelyconnected to the rams in such a way that upon closing movement of thearms fluid is displaced into the reservoir thus producing a forcetending. to open the arms when the magnet blockis de-energised. Thisforce, which could be supplemented by a mechanical spring, helps toovercome the residual magnetic force.

The two parts of the core assembly can be arranged in any suitable way.The first part is preferably rigidly connected to a first sleeveslidable on a pillar extending FIG. 1 shows a conventionalelectro-magnetic grab consisting of a crane 1 from which hangs a hook 2on which a magnet block 3 is suspended by chains 4. For picking upmagnetic material such as steel scrap the block is electricallyenergised to attract the magnetic material and upon de-energisation thescrap will be dropped. Apparatus 5 for adapting the electromagnetic grabfor the handling of non-magnetic material such as non-magnetic metalscrap is shown on the ground before being connected to the grab.

The apparatus 5 includes a frame 6 at the top of which there is a recess7 into which the magnet block 3 can be inserted upon relative lateralmovement between the block 3 and frame 6. The top of the frame 6 has anannular plate 8 with an opening 9 which forms a passage for the chains 4when the block 3 is being in serted into the frame 6. The frame 6 isformed by the plate 8, a wall 10, four plates 15 connected to the wall10, a ring 11 connected to the bottom of the wall 10, and a bottommember 12 connected to the plates 15.

Four curved lifting arms 13 are pivotally connected to the plates 15 ofthe frame 6 by pivot pins14. A core assembly 16 of magnetic materialsuch as soft iron is slidably mounted within the frame 6 on a pillar 17connected to the bottom member 12 and extending vertically within theframe 6. The core assembly 16 is formed intwo parts 18 and .19. Thefirst part 18 is rigidly connected to a first sleeve 20 surrounding andslidable on the pillar 17. The second part 19 is rigidly connected byarms 22 to a second sleeve 21 surrounding the first sleeve 20 andslidable relative to the first sleeve 20. The first part 18 is formed oftwo rings rigidly connected together, and surrounding the pillar 17, andthe second part 19 is also formed of two rings rigidly connectedtogether and surrounding the first part 18.

A stop 23 connected to the pillar 17 limits downward movement of thesleeve 20. In use, upward movement of the sleeve 20 is limited bycontact of the first part 18 with the magnet block 3. A projection 24 onthe sleeve 20 limits downward movement of the sleeve 21 on the sleeve20, and in use upward movement of the sleeve 21 on the sleeve 20 islimited by contact of the second part 19 .with the magnet block 3.. Asshown in FIG. 4 when the sleeve 20 is in contact with the stop 23 andwhen the sleeve 22 is in contact with the projection 24 the uppersurface of the part 18 is higher than the upper surface of the part 19.

A rubber bellows 25 is connected between the stop 23 and the lower endof the sleeve 21 to seal the assembly 16 against dirt. A rubber bellows26 is connected between the upper end of the pillar 17 and the sleeve20, and a further bellows 27 is connected between the upper end of thesleeve 21 and the lower side of the core part 18 also to seal theassembly 16 against dirt.

The arms 13 and the core assembly 16 are operatively connected so thatmovement of the core assembly 16 towards the magnet block 3 closes thearms 13 into a material holding position. A piston and cylinder assembly28 is connected between the arms 22 of the core assembly 16 and theframe 6 adjacent to each arm 13, and a hydraulic ram 29 interconnectseach arm 13 and the frame 6. The piston rod end of each assembly 28 ispivoted to the arm 22 and the piston rod end of each ram 29 is pivotedto its associated arm 13. A pressurisable reservoir 30 for hydraulicfluid is disposed within the pillar 17 and a hydraulic lead 31 connectsthe reservoir with the piston rod end of the cylinder of each ram 29. Ahydraulic lead 32 connects the other end of the cylinder of each ram 29with the piston rod end of the'associated cylinder 28.

When not in use the apparatus stands on its arms 13 with-the arms 13open as shown in FIGS. 1 and 4 and the right hand side of FIG. 3. Thecrane driver can easily engagethe apparatus 5 with the magnet block 3.As shown in FIG. 4 the core part 18 is closer to the magnet block 3 thanthe core part 19. The crane 2 can lift the apparatus 5 and lower it onto a pile of nonmagnetic scrap. The weight of the apparatus 5 and theblock 3 force the arms 13 into the scrap until the member 12 rests onthe scrap. The block 3 is then energised whereupon the core part 18 isfirst attracted to its upper position into contact with the block 3.During this upward movement of the part 18 the part 19 is carriedtowards the block 3 because the sleeve 21 is in contact with theprojection 24. This upward movement of the part 19 together with thepart 18 results in a partial extension of the piston and cylinderassemblies 28 so that hydraulic fluid is displaced via leads 32partically to extend the rams 29. When the core part 18 has moved itsfull extent and is in contact with the block 3, the second part 19 willbe close enough to the block 3 to be attracted towards it and thisfurther movement of the part 19, during which the sleeve 21 will slideon the sleeve 20, results in more hydraulic fluid being displaced fromthe cylinder assemblies 28 into the rarns 29.

Displacement of fluid into the rams 29 from the lead 32 has two effects.First the arms 13 move into the closed position, and second, fluid isdisplaced from the rod end of the cylinders of the rams 29 into thereservoir 30. The reservoir effectively stores energy during movement ofthe arms 13 to the closed position so that upon de-energisation of themagnet block 3 a force is exerted tending to move the core assembly awayfrom the magnet block 3.

When the arms 13 are closed the crane 1 can lift the magnet block 3together with the apparatus 5 and scrap. When the magnet block 3 isde-energised the weight of the scrap and the core assembly 16 provides amoment about the pivots 14 to open the arms and release the scrap. Theforce produced by the reservoir 30 will add to the moment and will helpto overcome any residual magnetic force which, with a light load in thearms 13, might otherwise prevent the arms 13 from opening.

The apparatus described above enables a conventional electro-magneticgrab to be quickly modified for use with non-magnetic materials.However, the apparatus could be permanently attached to a magneticblock. The provision of the cores assembly in two parts as describedenables heavier loads to he lifted than could be lifted otherwise.

We claim 1. Apparatus attachable to an electro-magnetic grab forhandling non-magnetic materials including: a frame connectible to thegrab, lifting arms movable relative to the frame, and a core movablerelative to the frame, the arms and the core being operatively connectedtogether so that, in use, when the frame is connected to the grab,energisation of the magnet block of the grab will attract the coretowards the block thus closing the arms into a material-holdingposition, subsequent deenergisation of the block allowing the arms toopen into a fully open material-releasing position, the core beingformed in two parts of magnetic material capable of limited relativemovement, the parts being arranged so that in the fully open position ofthe arms the first part is located closer to the magnet block than thesecond part, movement of said first part towards the block carrying saidsecond part towards the block and partially closing the arms, and saidsecond part being capable of further movement towards the block afterthe first part has moved its full extent in order to complete theclosing movement of the arms.

2. Apparatus as claimed in claim 1 in which said second part isconnected to a piston and cylinder assembly arranged so that uponmovement of said second part towards the magnet block fluid is displacedto actuate fluid operated rams connected to the arms.

3. Apparatus as claimed in claim 2 including a pressurisable fluidreservoir operatively connected to the rams in such manner that, uponclosing movement of the arms, fluid is displaced into the reservoirproducing a force tending to open the arms when the magnet block isde-energised.

4. Apparatus as claimed in claim 3 in which said first part of the coreassembly is rigidly connected to a first sleeve slidable on a pillarextending within the frame.

5. Apparatus as claimed in claim 4 in which said second part is rigidlyconnected to a second sleeve slidably mounted relatively to said firstsleeve.

6. Apparatus as claimed in claim 4 wherein said pressurisable reservoiris disposed within said pillar.

1. Apparatus attachablE to an electro-magnetic grab for handlingnon-magnetic materials including: a frame connectible to the grab,lifting arms movable relative to the frame, and a core movable relativeto the frame, the arms and the core being operatively connected togetherso that, in use, when the frame is connected to the grab, energisationof the magnet block of the grab will attract the core towards the blockthus closing the arms into a material-holding position, subsequentde-energisation of the block allowing the arms to open into a fully openmaterial-releasing position, the core being formed in two parts ofmagnetic material capable of limited relative movement, the parts beingarranged so that in the fully open position of the arms the first partis located closer to the magnet block than the second part, movement ofsaid first part towards the block carrying said second part towards theblock and partially closing the arms, and said second part being capableof further movement towards the block after the first part has moved itsfull extent in order to complete the closing movement of the arms. 2.Apparatus as claimed in claim 1 in which said second part is connectedto a piston and cylinder assembly arranged so that upon movement of saidsecond part towards the magnet block fluid is displaced to actuate fluidoperated rams connected to the arms.
 3. Apparatus as claimed in claim 2including a pressurisable fluid reservoir operatively connected to therams in such manner that, upon closing movement of the arms, fluid isdisplaced into the reservoir producing a force tending to open the armswhen the magnet block is de-energised.
 4. Apparatus as claimed in claim3 in which said first part of the core assembly is rigidly connected toa first sleeve slidable on a pillar extending within the frame. 5.Apparatus as claimed in claim 4 in which said second part is rigidlyconnected to a second sleeve slidably mounted relatively to said firstsleeve.
 6. Apparatus as claimed in claim 4 wherein said pressurisablereservoir is disposed within said pillar.